#298 Expose remaining pan available. Allows activities and subclasses to determine whether pan limit has been reached in each direction.

1 files changed, 31 insertions, 0 deletions

diff --git a/library/src/main/java/com/davemorrissey/labs/subscaleview/SubsamplingScaleImageView.java b/library/src/main/java/com/davemorrissey/labs/subscaleview/SubsamplingScaleImageView.java
index 8bf9153..e66b8fe 100644
--- a/library/src/main/java/com/davemorrissey/labs/subscaleview/SubsamplingScaleImageView.java
+++ b/library/src/main/java/com/davemorrissey/labs/subscaleview/SubsamplingScaleImageView.java
@@ -2336,6 +2336,37 @@ public class SubsamplingScaleImageView extends View {
     }
 
     /**
+     * Calculate how much further the image can be panned in each direction. The results are set on
+     * the supplied {@link RectF} and expressed as screen pixels. For example, if the image cannot be
+     * panned any further towards the left, the value of {@link RectF#left} will be set to 0.
+     */
+    public final void getPanRemaining(RectF vTarget) {
+        if (!isReady()) {
+            return;
+        }
+
+        float scaleWidth = scale * sWidth();
+        float scaleHeight = scale * sHeight();
+
+        if (panLimit == PAN_LIMIT_CENTER) {
+            vTarget.top = Math.max(0, -(vTranslate.y - (getHeight() / 2)));
+            vTarget.left = Math.max(0, -(vTranslate.x - (getWidth() / 2)));
+            vTarget.bottom = Math.max(0, vTranslate.y - ((getHeight() / 2) - scaleHeight));
+            vTarget.right = Math.max(0, vTranslate.x - ((getWidth() / 2) - scaleWidth));
+        } else if (panLimit == PAN_LIMIT_OUTSIDE) {
+            vTarget.top = Math.max(0, -(vTranslate.y - getHeight()));
+            vTarget.left = Math.max(0, -(vTranslate.x - getWidth()));
+            vTarget.bottom = Math.max(0, vTranslate.y + scaleHeight);
+            vTarget.right = Math.max(0, vTranslate.x + scaleWidth);
+        } else {
+            vTarget.top = Math.max(0, -vTranslate.y);
+            vTarget.left = Math.max(0, -vTranslate.x);
+            vTarget.bottom = Math.max(0, (scaleHeight + vTranslate.y) - getHeight());
+            vTarget.right = Math.max(0, (scaleWidth + vTranslate.x) - getWidth());
+        }
+    }
+
+    /**
      * Set the pan limiting style. See static fields. Normally {@link #PAN_LIMIT_INSIDE} is best, for image galleries.
      */
     public final void setPanLimit(int panLimit) {